A New Phase in the Ti-AI-O System: Its Significance for TIAI Oxidation

摘要

The oxidation rates of binary and ternary, Crcontaining #gamma#-TiAl based materials during oxidation inAr/O2 are correlated with the composition and microstructure ofthe subsurface depletion layer. Beneath the initially formedprotective alumina scale, the depletion layer consists not of#alpha#2-Ti3Al but of a cubic Z-Phase. Appearance of a2 in thedepletion layer and finally contact of this phase with the inneroxide interface leads to internal aluminium oxidation,accompanied by a further enhancement of scale growth rate.